Iselle weakened further early Friday, but remains a tropical storm packing maximum sustained winds of 50 mph as of 8 a.m. Friday. A tropical storm warning is in effect as of 8 a.m. Friday.

The tropical storm made landfall around 2:30 a.m. on the Big Island and was forecast to deluge the island with up to 12 inches of rain late Thursday and Friday, according to the Central Pacific Hurricane Center and National Weather Service.

Wind gusts and storm surge began to buffet windward Hawaii Island Thursday afternoon as Hawaii Police drove through Keaukaha in East Hawaii, using loudspeakers to urge residents to voluntarily evacuate. Surf kicked up and bands of rain began moving in around noon.

“On the Big Island, we’re looking at 60-70 mph wind and gusts to 85 in the highest areas,” said Chris Brenchley, forecaster with the National Weather Service, at a 2 p.m. press conference in Honolulu.

At that time, winds were reaching 60 mph on the summit of Mauna Kea, 50 mph in Waimea and 45 mph in Volcano, Brenchley said.

“This just the beginning,” he said.

Iselle was 70 miles west-southwest of Hilo and 85 miles west-southwest of Kailua-Kona, and moving west at 20 mph Friday at 5 a.m. Winds were expected to damage buildings and topple trees and some power poles as the hurricane passed directly over the island Thursday night.

Hawaii County Civil Defense on Thursday advised residents of coastal areas of Punaluu in Ka‘u and Kalapana, Kapoho and Pohoiki in Puna, to take precautions, and those living along immediate shorelines to consider getting to higher ground.

The windows of most of the businesses along Kamehameha Avenue in downtown Hilo were boarded up to break Iselle’s blast. By 1 p.m. Thursday, calls were beginning to come in to the Civil Defense Emergency Operations Center in Hilo with residents reporting rain and concerns about rising streams, said Bobby Jean Leithead Todd, the county’s environmental management director.

“People seem to be calm but hunkering down. They’re taking this seriously,” Leithead Todd reported from the EOC.

Civil Defense advised drivers to stay off roads as of noon Thursday. A predicted storm surge of 1 to 3 feet on top of a 2.8-foot high tide Thursday afternoon set the stage for flooding along the coast and in low-lying areas especially along the windward side. Surf in the range of 15 to 25 feet Thursday night was expected to add to flooding in coastal areas, according to a NWS hurricane warning.

People who chose to use hurricane shelters were urged to leave early so they would not be caught in torrential rains and dangerous winds. Residents staying at home were asked to turn off propane sources, unplug small appliances, fill their bathtubs with water and put their refrigerators on maximum cold and keep them closed in anticipation of possible widespread power outages.

Gov. Neil Abercrombie said the state stands ready to respond to Iselle.

“There are no glum faces here because we are confident we are ready to respond … and we are ready to begin the recovery to the extent necessary,” Abercrombie said at the press conference. “People should be calm and prepared to take directions from Civil Defense.”

Hurricane Julio meanwhile weakened early Friday, but remains a Category 2 storm packing 105 mph winds about 870 miles east of Hilo. The cyclone, moving west at about 16 mph, is poised to pass through an area of light vertical shear but also sea surface temperatures in the 77 to 78 degree range that over the next couple of days should gradually weaken the system, according to NWS bulletins. Julio could still be a Category 1 hurricane as it comes abreast the islands Sunday.

The forecast track shows the system passing just to the north of the Big Island. But it’s too early to know where Julio will go, Brenchley said.

“There is the potential we could have pre-saturated grounds from Iselle that could exacerbate flooding,” Brenchley said. “Julio could follow Iselle or go north. It’s still to far out to tell.”